It's not clear if the efficiency is for the stack alone (probably) or for the complete system, or what the cost and efficiency loss of fuel preparation would be. If the cells are aimed at use in coal plants, it seems likely that they will take scrubbed syngas (CO + H2 + inert gases) as their fuel and require no further reformation. If fuels like methane and propane require no preparation and the 49%-efficient stack is followed by a 95%-efficient converter, the fuel-to-juice efficiency would be 46.6%. That's not half bad.

The system cost for cells such as these is not easily pinned down [1], but if we assume $600/kW we probably won't be far off. Last, we need a total system efficiency. Condensing furnaces exceed 95%, so that seems like a completely reasonable assumption.

If we assume 46.6% electrical efficiency and 95% total efficiency (48.4% output as heat, 5% losses) here's what we'd get out of a therm of natural gas, assuming a price of 65¢/therm for gas and $.68/therm for the produced heat:

Product

Quantity

Units

Value/unit

Total value

Electricity

13.65

kWh

$0.08

$1.09

Heat

0.484

therm

$0.68

$0.33

TOTAL

$1.42

Looks like the unit would just about double your money. If you had a 5 kW unit running at 25% capacity factor for the year (providing both space heat and DHW), it would consume 802 therms of gas at a cost of $521 and yield heat and electricity worth $1139. The gross profit before depreciation and maintenance would be $618/year, sufficient to pay off a $3000 unit in 5 years.

Most households don't use 5 kW of electricity during the heating season except for electric stoves or heat pumps. I haven't looked at the net efficiency of the fuel cell plus heat pump in at least a week, so it's time to scribble on another envelope. 5 kW into a heat pump with an EER of 12 would yield 60,000 BTU/hr. The example fuel cell system producing 5 kW would burn 0.366 therm/hour of gas and yield 17,700 BTU/hr of heat; together, the two could produce 77,700 BTU/hr of heat from 36,600 BTU/hr of gas. This is an EER of 212%, cutting fuel requirements by 54% compared to a 98%-efficient condensing furnace.

I'll come back and look at the combo of FC/heat pump plus wind power and PHEV later. For now, it looks like a replacement of gas furnaces with FC/heat pump combos could offset quite a few years of natural gas depletion, and make it even cheaper to adopt alternative energy supplies when we develop them (so long as they're SOFC-compatible). Samples suitable for these purposes are in testing at the Department of Energy, and the projected price is right.

I don't remember why I posted a comment or how I came to view your "work." Regardless, the one feeling I get reading you. You use the web to crap out your thoughts because you don't have the ability or nerve to speak your mind to someone's face. I sure hope you get paid to come up with all this crap. You have the ability to research, write and present. It would be a huge waste if this was your only outlet.